"Tim Wescott" wrote in message
...

Having a problem that goes away like that is a plus, because you can put
your probe on a suspect signal and look for it changing as the radio
fails.

Good suggestions. I would add that you should find out if it happens on all
bands (you didn't say). If so, then the VFO or premixing circuits may be the
problem. If you know the VFO frequency you can listen for it on another
receiver, with an antenna wire close to the VFO box. You can make a simple
RF probe for your voltmeter. Here is a link:
http://www.io.com/~n5fc/rfprobe1.htm You don't have to worry about the exact
voltage now. Just find out where the voltage drops when the radio quits
working. Start at the output of the VFO and follow the signal through. In
addition to a part that fails when it gets hot, you may also find a bad
solder connection on a circuit board, that also fails when it gets hot. Or
the pin on a connector may be corroded (or loose, and bending enough under
heat to break the connection). If you follow the signal from the beginning,
you will eventually find the place where it stops. Then you know where to
look. (Hint: Look for signs of overheating, like a dark place on the bottom
of a circuit board.) Bad solder connections are sometimes very hard to see.
If you suspect one, you can reheat it and see if that fixes the problem.

73,

"PM"